Calorimetric properties of degenerative human shoulder joint hyaline cartilage

The glenohumeral joint is not a classical mass bearing joint, the treatment of primary osteoarthritis is conservative. In all other cases, when the arthritis is associated with unbalance of the soft tissues, the treatment solution of this pathology is arthroplasty. The purpose of this study was to examine the altered metabolism in human degenerated cartilage of the shoulder joint. With the rise of temperature an endothermic reaction was observed in all cases. The use differential scanning calorimetry as part of thermal analysis was a reliable method for differentiating normal hyaline cartilage from degenerated samples.     

Novel calorimetric properties of human cartilage samples in rheumatoid arthritis

During recent years, knowledge of rheumatoid arthritis has increased, and management of the disease has improved. A limited number of papers have been published before on the subject of thermal analysis of degenerative cartilage but rheumatoid arthritis (RA) has not been studied previously. A new protocol had to be established before the investigation. The purpose of this study was to further characterize the altered metabolism in human RA cartilage that promotes disease progression. Previously, these methods have not been used for this purpose. The use of thermal analysis could be an effective method for controlling the relationship between biomarkers and disease progression.     

New thermogravimetric protocol for the investigation of normal and damaged human hyaline cartilage

Osteoarthritis, although classically conceived of as a degenerative consequence of aging, is a disease with an increasingly well-characterized molecular pathophysiology. Pathologic changes in cartilage composition and molecular organization, as well as elevated water content, alter the exquisite balance of biomechanical properties. Much of what is known about changes in the extracellular matrix in osteoarthritis comes from animal models. Previously, thermogravimetric methods have not been used for compositional thermoanalytical study of normal and degenerative human hyaline cartilage. For this reason the research group established a sufficient new thermogravimetric protocol, which proved water content elevation contributing to disease progression.     

Thermal analysis of the osteoarthritic human hyaline cartilage

Summary Arthritis of major joints, especially osteoarthritis of the knee is a very frequent disease of human beings mainly in the developed countries. The pathology of osteoarthritis has been subject of many publications before, using a wide spectrum of different methods to evaluate degenerative changes of hyaline cartilage. The authors examined osteoarthritic human knee joint hyaline cartilage with differential scanning calorimetry. The different stages of cartilage degeneration have been verified by histological examinations. The research group demonstrated thermal differences between various stages of osteoarthritis. Besides explaining possible causes for experienced thermodynamic effects, the authors reflect upon future research ways and the possibilities of applying the method in practice.     

Characterization of human cartilage in degenerated spine disease with differential scanning calorimetry

The purpose of this study was to further characterize the altered metabolism spondylolisthesis that promotes disease progression. Degenerative human cartilage (intervertebral disc, facet joint and vertebral end-plate) was obtained during 15 posterior lumbar spine interbody fusion procedures performed at the University of Szeged. The thermal properties of samples were determined by differential scanning calorimetry (Mettler-Toledo DSC 821^e). Greatest change in the enthalpy was observed in the intervertebral disc samples: −1600.78 J g⁻¹. Denaturation caused by heating in the normal human hyaline cartilage needed −1493.31 J g⁻¹ energy. Characterization of the altered metabolism that promotes disease progression should lead to future treatment options.     

Differential scanning calorimetric examination of the tracheal cartilage after primary reconstruction with differential suturing techniques

Summary Resection and subsequent end-to-end anastomosis of the windpipe is a tried-and-tested acceptable method for the surgical treatment of segmental defects. There are a variety of different techniques for tracheal end-to-end anastomosis, but controversial reports highlight the fact that the suturing technique of the anastomosis is still subject of debate. We aimed to show the postoperative effects of the continuous and simple interrupted suturing technique respectively on the tracheal cartilage using differential scanning calorimetry. Transsection and subsequent reanastomosis of the cervical trachea was performed in 14 adult beagle dogs. The trachea was anastomized with continuous or simple interrupted sutures respectively depict no change in microcirculation after the resection of the trachea, but significant decrease following the completion the anastomosis with continuous sutures. Conventional histological analysis did not show any marked postoperative change in the tracheal cartilage but our DSC scans clearly demonstrated the differences between the intact cartilages and the ones involved in the anastomosis.     

Differential scanning calorimetric examination of the tracheal cartilage after primary reconstruction with continuos sutures: A preliminary study

Acquired upper airway stenosis is usually associated with a complex of pathological conditions at the high tracheal and the subglottic levels. Reported reconstructive techniques include widening of the airways by incorporation of grafts, segmental resection, and anastomosis or combined procedures. Progress in anaesthesia, surgical techniques, and understanding of the pathophysiology of the trachea has made primary tracheal reconstruction a safe operative procedure, although there are no reports observing its acute effect on the tracheal cartilage. Differential scanning calorimetry (DSC) is a well-established method for the demonstration of thermal consequences of local and global conformational changes in biological systems, including hyaline cartilage, but it has never been applied for the investigation of tracheal cartilage. According to the present study, the thermograms may prove the presence of structural changes of the cartilage after primary reconstruction in the short-term follow up (smaller melting temperature and calorimetric enthalpy in the operated dog). The differences were clearly demonstrated between the intact cartilages and the ones involved in the anastomosis.     

Differential scanning calorimetric examination of the human hyaline cartilage of the femoral head after femoral neck fracture

The femoral neck fracture continues to be unsolved fractures and the guidelines for management are still evolving. The primary complications arising from femoral neck fractures are non-union and avascular necrosis. The various methods currently available for predicting the vascularity of the head at the time of fracture are not sufficiently quantitative to be used on a routine clinical basis. The hypothesis was that after the femoral neck fracture there are clear pathological abnormalities in the cartilage of the femoral head, which could be monitored besides the classical methods by differential scanning calorimetry. The thermal denaturation of human samples was monitored by a SETARAM Micro DSC-II calorimeter. All the experiments were performed between 0 and 100 °C. The heating rate was 0.3 K/min. DSC scans clearly demonstrated significant differences between the control and different stages avascular samples (control, fresh fractures: T _m  = 68.2 °C, ΔH _cal = 2.87 J/g, avascular necrosis: T _m  = 70.7 °C, ΔH _cal = 3.61 J/g,). These observations could be explained with the structural alterations caused by the biochemical processes during the degeneration of the cartilage due to avascular femoral head necrosis. With the investigations the authors could demonstrate that DSC is a useful and well-applicable method for the investigation of hyaline cartilage of the fractured human femoral head. It was confirmed significances between the changes of calorimetric results and the elapsed time from the primary femoral neck fracture.     

Differential sacnning calorimetric examination of the human intervertebral disc: establishment of calorimetric standards of different stages of degeneration

Intervertebral disc (IVD) degeneration is a common orthopaedic disorder with significant social and economic impact. The major pathological changes occur in the structure of anulus fibrosus (AF) and nucleus pulposus (NP). According to previous reports differential sacnning calorimetric (DSC) proved to be a suitable method for the demonstration of thermal consequences of local and global conformational changes in the structure of the human intervertebral discs. According to the present study, the DSC results clearly proved that definitive differences are present between the stages of disc degeneration in calorimetric measures. The structural differences between the stages could be also demonstrated by histology.     

A new approach to the calorimetric investigation of physical and chemical transitions

The theoretical basis for Modulated DSC is described and the additional information in can give over conventional DSC illustrated for some polymers.     

Differential scanning calorimetric examination of the degenerated human palmar aponeurosis in dupuytren disease

The Dupuytren contracture - degenerative shortening of the palmar aponeurosis - is a common disease of the hand in Europe. The aetiology of the degenerative changes in the collagen structures is still not clear. To describe the clinical manifestation of the disease we use an international classification according to Iselin. Our hypothesis was that in Dupuytren disease there is a clear pathological abnormality in the tissue elements building up the palmar aponeurosis, which is responsible for the disease, and could be monitored besides the classical histological methods by differential scanning calorimetry. The thermal denaturation of different parts of human samples was monitored by a SETARAM Micro DSC-II calorimeter. All the experiments were performed between 0 and 100°C. The heating rate was 0.3 K min⁻¹. DSC scans clearly demonstrated significant differences between the different types and conditions of samples (control: T _m=63°C and ΔH _cal=4.1 J g⁻¹, stage I.: T _m= 63°C and ΔH _cal=5.1 J g⁻¹, stage II.: T _m=64°C and ΔH _cal=5.2 J g⁻¹, stage III.: T _m=60°C and ΔH _cal=5.2 J g⁻¹, stage IV.: T _m=60.2°C and ΔH _cal=5.3 J g⁻¹). The heat capacity change between native and denatured states of aponeurosis samples increased with the degree of structural alterations indicating significant water loosing. These observations could be explained with the structural alterations caused by the biochemical processes. With our investigations we could demonstrate that DSC is a useful and well applicable method for the investigation of collagen tissue of the human aponeurosis. Our results may be of clinical relevance in the future i.e. in the choice of the optimal time of surgical therapy of different clinical level Dupuytren contractures.     

DSC measurement of cartilage destruction caused by septic arthritis

Summary Treatment of a bacterial arthritis is a challenging task for a clinician as inadequate therapy can cause cartilage destruction and can result in severe osteoarthritis of the affected joint. The development of cartilage destruction in septic arthritis is not known in details. The aim of this study was to follow this process by calorimetric method. We induced experimental septic arthritis in knee joints of seven New Zealand rabbits by single inocculation of Staphylococcus aureusOKI 112001 culture (1.5 mL 8·10⁸±5% c.f.u.). The first rabbit died on the 11^thday. At that time all the other subjects were made overslept and samples were isolated from the cartilage of the femurs for calorimetric measurement. The DSC scans clearly demonstrated the development of infective structural destruction in cartilage from the first to the tenth day of incubation. In case of healthy control the melting temperatures (T_m) were: 49.7, 55 and 63.4°C and the total calorimetric enthalpy change (ΔH) was 0.55 J g^-1. After the first day the enthalpy decreased (0.375 J g^-1), the first two transition temperature shifted towards higher temperature: 57 and 63.15°C. Up to the fourth day the effect of infection culminated with T_mof 49.3, 55.9, 59.4, 62.8°C and further decrease of the ΔH. At the fifth day the effect of infection is culminated in two separable thermal denaturation events (with 55 and 63.3°C T_ms) with high jump in ΔHindicating the dramatic change of the structure of rabbit cartilage, so this time elapsed seems to be critical from the point of view of practical clinical relevance too. Between the 7^thand 11^thdays practically we had same melting temperatures (50 and 63°C) with low (~0.24 J g^-1) enthalpy.     

Thermal analysis of the cruciate ligaments of the human knee

Summary Cruciate ligaments of the knee joint are important structures very often affected by the degenerative process in case of osteoarthritis. One of the most controversial issues in knee arthroplasty practice nowadays is the role of the posterior cruciate ligament. With foregoing studies authors have demonstrated the feasibility of DSC in the investigation of the musculoskeletal system. With current study authors established the thermal behaviour of healthy cruciate ligaments and detected the alterations in case of osteoarthritis. By establishing the DSC scans of the normal ligaments authors demonstrated clear differences between the posterior and anterior ligament. In addition alterations between normal and arthritic samples could be detected both in terms of changes in total enthalpy and heat capacity. Calorimetric findings have been verified by histological examinations as well.     

TA of pval hydrogel cross-linked by chemical and eb irradiation process used as artificial articular cartilage

Hydrogels, in general, can be used as a compliant surface in prosthesis of human synovial joints due to their biocompatible characteristics. In this work, different hydrogels were prepared from two aqueous solutions of PVAL (15 and 20 mass/mass%) by chemical reactions using citric acid as a cross-linking agent and by electron beam (EB) irradiation with doses from 25 to 100 kGy. The hydrogels were evaluated by their mechanical properties through indentation creep test, thermal properties by differential scanning calorimetry (DSC), and also equilibrium water content (EWC). This revised version was published online in August 2006 with corrections to the Cover Date.     

Differential scanning calorimetric and histological examinations of the long head of the biceps in cadavers

Shoulder pain is a common presentation of the dysfunction of the glenohumeral joint. The long head of the biceps tendon has been proposed as a source of pain in rotator cuff pathologies. The rotator cuff is a dynamic stabilizer of the glenohumeral joint, and its tear can create different shoulder dysfunctions. The long head of the biceps has a special intraarticular localisation, so the arthricular destruction affects its tendon too. In the process of the rotator cuff degeneration and tear the structure of the biceps tendon pathological transforms. With foregoing studies authors have demonstrated the feasibility of DSC in the investigation of the musculoskeletal system. The aim of this study was to establish the curves and the histological properties of the tendon of the long head of the biceps in different magnitudes of the rotator cuff tear on cadavers. The DSC results clearly proved that definitive differences are present between the structural state of the tendons in different magnitudes of the rotator cuff tears, which have also been demonstrated by the histological examination.     

DSC study of the association of ethanol with human serum albumin

Human serum albumin unfolding in ethanol/water mixtures was studied by use of differential scanning calorimetry. Ethanol-induced changes in DSC curves of defatted and non-defatted albumin were markedly different. In the presence of ethanol, bimodal denaturation transition for fatty acid free albumin was observed while that for albumin containing endogenous fatty acids was single and more sharpen than in aqueous solution. Ethanol was found to decrease the thermal stability of albumin due to the binding to the unfolded state to a higher degree than to the native state, thus favouring unfolding. The binding with different affinities has been suggested depending on ethanol concentration range.     

毛细管整体柱在线二维分离系统应用于人体软骨的蛋白质组分析

将已建立的 7 cm 柱长的磷酸基团强阳离子交换富集整体柱与85 cm柱长的C12烷基反相整体柱结合的在线二维分离平台应用于软骨提取蛋白的蛋白质组分析。对20 μg软骨提取蛋白的酶解产物进行14个盐梯度的分级,然后对14个馏分进行反相色谱梯度分离及串联质谱鉴定,成功地鉴定得到了7434个独立肽段对应的1901个非冗余蛋白质。对所鉴定到的蛋白质进行定位分类,结果表明鉴定到的大部分蛋白质是来自于软骨细胞内部的低丰度蛋白质,这对于许多关节类疾病的研究有重要意义。     

Humidity controlled calorimetric investigation of the hydration of MgSO4 hydrates

The isothermal heat of hydration of MgSO₄ hydrates was studied by humidity controlled calorimetry. Two hydrates, starkeyite (MgSO₄·4H₂O) and a mixture of MgSO₄ hydrates with summary 1.3 mol H₂O were investigated. The solid-gas reactions were initiated at 30°C and 85% relative humidity. The heat of hydration was determined in a circulation cell in the calorimeter C80 (Setaram). The crystal phases formed after the hydration process were analyzed by thermogravimetry (TG) and X-ray powder diffraction (XRD). Starkeyite reacted with the water vapour to the thermodynamic stable epsomite and the MgSO₄ hydrate mixture with 1.3 mol water to hexahydrite. The hydration heats of starkeyite and the mixture were determined to be −169±3 and −257±5 kJmol⁻¹, respectively.     

Application of a simple calorimetric data analysis on the binding study of calcium ions by human growth hormone

A simple graphical linear method was introduced for isothermal titration calorimetric data analysis in the protein-ligand interaction. The number of binding sites, the dissociation binding constant and the molar enthalpy of binding site can be obtained by using this new isothermal titration calorimetric data analysis method. The method was applied to the study of the interaction of human growth hormone (hGH) with divalent calcium ion at 27°C in NaCl solution, 50 mM. hGH has a set of three identical and independent binding sites for Ca ²⁺ . The intrinsic dissociation equilibrium constant and the molar enthalpy of binding are 52 μMand -17.4, respectively. Results obtained by this new calorimetric data analysis are in good agreement with results obtained using our previous method.     

Modulation of cartilage differentiation by melanoma inhibiting activity/cartilage-derived retinoic acid-sensitive protein (MIA/CD-RAP)

Melanoma inhibiting activity/cartilage-derived retinoic acid-sensitive protein (MIA/CD-RAP) is a small soluble protein secreted from malignant melanoma cells and from chondrocytes. Recently, we revealed that MIA/CD-RAP can modulate bone morphogenetic protein (BMP)2-induced osteogenic differentiation into a chondrogenic direction. In the current study we aimed to find the molecular details of this MIA/CD-RAP function. Direct influence of MIA on BMP2 by protein-protein-interaction or modulating SMAD signaling was ruled out experimentally. Instead, we revealed inhibition of ERK signaling by MIA/CD-RAP. This inhibition is regulated via binding of MIA/CD-RAP to integrin α5 and abolishing its activity. Active ERK signaling is known to block chondrogenic differentiation and we revealed induction of aggrecan expression in chondrocytes by treatment with MIA/CD-RAP or PD098059, an ERK inhibitor. In in vivo models we could support the role of MIA/CD-RAP in influencing osteogenic differentiation negatively. Further, MIA/CD-RAP-deficient mice revealed an enhanced calcified cartilage layer of the articular cartilage of the knee joint and disordered arrangement of chondrocytes. Taken together, our data indicate that MIA/CD-RAP stabilizes cartilage differentiation and inhibits differentiation into bone potentially by regulating signaling processes during differentiation.